Blast gate

ABSTRACT

A blast gate to control the application of vacuum pressure to a particulate generating machine so that particulate may be drawn away from the machine and isolated in a vacuum container. The blast gate may be opened when either a vacuum or particulate generating machine is switched on. The blast gate is designed to be inserted in a duct leading from the vacuum to the particulate generating machine. The electromechanical design allows two switches to be activated by a mechanical rotating arm. The switches respectively allow the gate to be held in the open position or in the closed position as well as activating the mechanical arm whereby the gate is moved to the open or closed position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/397,261, filed 9 Jun. 2010.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is used in vacuum collection systems as seen in machineshops where waste particulate is generated from the cutting, turning orshaping of wood, plastic, metal and like materials. Specifically, thisinvention relates to an electro-mechanical blast gate, that when open,allows the vacuum to reach and remove particulate from a particulategenerating machine or alternatively, when closed, isolates that machinefrom the vacuum system.

2. Description of the Related Art.

The inhalation of particulate matter associated with the cutting,turning and shaping of wood, plastic and metal have known adverse healtheffects. Further, the accumulation of particulate in the workspacecreates a fire hazard and, in some cases, a slip and fall hazard andadds to the general disorganization of the work area.

Blast gates are known in the art, however, they tend to be complex andexpensive. Their driving mechanism can be electrical, hydraulic orpressurized air. Most of these systems rely on a centralized controller.Because they are part of a larger extensive system, control lines mustbe extended to each gate thereby increasing the expense, complexity andthe chance of failure.

SUMMARY OF THE INVENTION

The invention presents a simple, electro-mechanical solution for thecollection and isolation of particulate matter in the work space. Ratherthan being part of a complex centralized system, the present inventioncan be attached to an individual machine and opened only when theparticulate generating machine or associated vacuum machine isactivated. This is especially effective when the shop is set up withvacuums individually attached to a machine or a single vacuum attachedto a discrete machine grouping.

The use of a single arm, rotating in a single direction which opens andcloses the gate results in efficient operation that can greatly reducegate failure due to its simplicity. Fully enclosing the gate in a sleeveprevents the accumulation of dust resulting in the binding of the gate,thus allowing reliable operation.

OBJECTS OF THE INVENTION

It is an object of the invention to allow vacuum pressure to aparticulate generating machine, thus allowing the removal of hazardousdust

It is an object of the invention to reduce the consumption of energy byopening only when a particulate generating machine or vacuum machine isactivated.

It is a further object of the invention to reduce the number of partsand the movement thereof to increase the reliability of the gate.

It is a further object of the invention to enclose the gate in a sleevewhereby particulate is prevented from binding or blocking gateoperation.

These and other objects and advantages are revealed in the accompanyingspecification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross section perspective side view of the blastgate.

FIG. 3 is a perspective view of the underside of the blast gate.

FIG. 5 is a perspective view of the upper side of the blast gate.

FIG. 7 is a partial cross section perspective view of the upper side ofthe blast gate.

FIG. 9 is a partial cross section perspective of the underside of theblast gate.

FIG. 11 is a side and top plan view of the driving arm in rotatingconfiguration.

FIG. 13 is a side and top plan view of the driving arm in stalledconfiguration.

FIG. 15 is an electrical schematic showing switch configuration of theblast gate closing.

FIG. 17 is an electrical schematic showing switch configuration of theblast gate in a closed position.

FIG. 19 is an electrical schematic showing switch configuration of theblast gate opening.

FIG. 21 is an electrical schematic showing switch configuration of theblast gate in an open position.

DESCRIPTION OF EMBODIMENTS

FIG. 1 illustrates a partial cross-sectional view of the Blast Gate. Thegate 2 is disposed within gate housing 4. Gate housing 4 is composed ofa gate housing upper surface 6, a gate housing lower surface 8, firstgate housing side 10, second gate housing side 12, and third gatehousing side 14 which are joined in such a way to form a pocket intowhich gate 2 is inserted, specifically, through gate housing open side16. Gate 2 is composed of a first planar gate segment 18 which slideswithin gate housing side 4. Second planar gate segment 20 is attached tofirst planar gate segment 18 and is perpendicular thereto. Upper gatehousing surface 6 exhibits first gate housing aperture 22. First ductconnector 24 is attached to upper gate housing surface 6 in such amanner as to be fully disposed over upper gate housing surface aperture22. A duct emanating from a vacuum is attached to first duct connector24.

Turning now to FIG. 3, lower gate housing surface 8 is shown. Acylindrical second duct connector 28 is disposed over second gatehousing aperture 26. A duct extending to the particulate generatingmachine is connected to the second duct connector. FIG. 3 also showscontroller housing 30. Controller housing 30 is composed of uppercontroller housing 32 and lower controller housing 34. The controllerhousing 30 is attached to the gate housing 4 by means of a firstperforated bracket 36 and second perforated bracket 38 which are fixedto gate housing lower surface 8. Lower controller housing 34 exhibitsfirst connector wing 40 and second connector wing 42, which arerespectively connected to first bracket 36 and second bracket 38.

FIG. 5 further illustrates the relative placement of upper controllerhousing 32 and lower controller housing 34. Upper controller housing 32is secured to lower controller housing 34 by means of any standardfastener through corresponding perforations. First controller housingconnector wing 42 is shown with perforations 44 which correspond toperforations in the first bracket 38. A similar configuration is seenbetween first connector wing 40 and second bracket 36.

FIG. 7 shows upper controller housing 32 covering motor 46. Motor 46 isan AC synchronous motor similar to commercially available Polyvolt PNSG-J6L8-24-6. Motor 46 is fixed to lower controller housing top surface48.

Moving now to FIG. 9, it can be seen that lower controller housing topsurface underside 112 is perforated such that motor shaft 50 extendsthrough lower controller housing top surface 48 by way of top surfaceaperture 52.

Driving arm 54 is L-shaped and exhibits driving arm first end 56,driving arm second end 58, and driving arm spacer segment 60. Drivingarm spacer segment 60 holds driving arm 54 away from lower controllerhousing top surface underside 112 such that driving arm 54 may pass overfirst switch 62 as driving arm 54 traces its circular path within lowercontroller housing 34. Driving arm spacer segment 60 is formed as partof driving arm 54 and is attached to driving arm second end 58. Drivingarm second end 58 and driving arm spacer segment 60 are perforated,allowing motor aperture 50 to be disposed within driving arm second endaperture 64. Driving arm first end 56 also exhibits driving arm firstend aperture 66, through which switch activating pin 68 is disposed. Asdriving arm 54 traces its rotational path within lower controllerhousing 34 and passes over first switch 62, the switch activating pin 68makes contact with first switch rocker 70. Switch activating pin 68 isrotatably disposed within driving arm first end aperture 66 but isfixedly attached to slotted bracket 72, allowing slotted bracket 72 torotate relative to driving arm 54. Slotted bracket 72 exhibits slot 74through which second planar gate segment 20 is disposed. It can be seenthat, as driving arm 54 traces its rotational path within lowercontroller housing 34, slotted bracket 72 will withdraw gate 2 fromwithin gate housing 4, thereby no longer occluding first gate housingaperture 22, and second gate housing aperture 26. It can also be seenthat as driving arm 54 continues through its rotational path, slottedbracket 74 will slide along the length of second planar gate segment 20.

FIG. 9 illustrates driving arm 54 at a point in its rotational pathwhereby gate 2 is inserted within gate housing 4. In FIG. 9, driving arm54 is exhibiting a clockwise rotation. As driving arm 54 continues itclockwise rotation, driving arm 54 rotates away from gate housing 4 and,consequently, as slotted bracket 72 slides along gate 2, it willwithdraw gate 2 from gate housing 4.

Turning again to FIG. 7, first switch 62 is illustrated attached tolower controller housing top surface underside 112, directly opposite tosecond switch 76. It can be seen that when driving arm 54 continues onits clockwise rotational path, switch activating pin 68 will come intocontact sequentially with second switch rocker arm 78 as well as firstswitch rocker arm 70.

FIG. 11 illustrates driving arm 54 with the internal slip clutchmechanism 80. Internal slip clutch mechanism 80 is composed ofcompression spring 82, compression spring set screw 84, and ball 86.Internal slip clutch mechanism 80 is disposed within slip clutchaperture 114 which extends from driving arm second end 58 throughdriving arm second end aperture 64. Ball 86 rests against compressionspring first end 88. Compression spring second end 90 rests againstcompression spring set screw 84. Compression spring 82 is compressedagainst compression spring set screw 84 and ball 86, forcing ball 86against motor shaft indent 92. When the torque exerted by motor 46 is ofinsufficient force to overcome the compression of compression spring 82exerts against ball 86 which, in turn, is exerted against the motorshaft indent 92, driving arm 54 will rotate in conjunction with therotation of motor shaft 50. This is the configuration seen in FIG. 11.

Turning now to FIG. 13, should the driving arm 54 bind or encounter anobstacle, causing it to stop its rotational path, the force of therotation of motor shaft 50 would then overcome the compression force ofcompression spring 82. Should this occur, ball 86 would be forced up theslip clutch aperture 114. This would allow the motor shaft 50 tocontinue to rotate within driving arm second end aperture 64 withdriving arm 54 remaining stationary. Slip clutch Aperture 114 exhibitsslip clutch aperture first end 96 which is a smooth bore and slip clutchaperture second end 95 which is threaded whereby compression spring setscrew 84 may be threadedly disposed.

Now turning to FIG. 15, we see a schematic showing an electrical powersource 100 connected to first common electrical line 102 which is, inturn, connected to first motor pole 104. The second common electricalline 106 is connected to blast gate control switch 108. When the blastgate control switch is in the position illustrated in FIG. 15, and whenfirst switch 62 is closed, the motor 46 is electrified through motorpole switch 110.

In this configuration, the motor 46 has been energized and starts torotate the driving arm 54. Driving arm 54 then rotates in a clockwisefashion until such time as switch activating pin 68 comes into contactwith first switch 62 breaking first switch circuit 116 and causing thedriving arm 54 to stop rotating. Blast gate control switch 108 isactivated in conjunction with the on/off switch of the individualparticulate generating machine, whether it be a table saw, band saw,lathe, or other machine. Thus, when the particulate generating machineis switched off, or alternatively, when a vacuum machine is switchedoff, the blast gate control switch 108 closes first switch circuit 116,thus allowing the motor to rotate.

Turning now to FIG. 17, here switch activating pin 68 now depresses thefirst rocker arm switch 70 which opens the circuit and stops therotational force of the motor 46. In this position, the driving arm 54has moved slotted bracket 72 toward gate enclosure 4 and, consequently,gate 2 has been inserted into gate enclosure 4 to its maximum extent,thereby closing the gate housing apertures 22 and 26.

Turning now to FIG. 19, we see that the particulate generating machinehas now been turned on, or alternatively the vacuum machine has beenturned on, thereby breaking first switch circuit 116 and causing blastgate control switch 108 to close second switch circuit 118. With secondswitch circuit 118 closed, electrical current is provided to motor pole110, resulting in the operation of the motor 46 rotating the driving arm54 again in a clockwise direction. The driving arm 54 will continue toswing through its rotational path until switch activating pin 68 makescontact with second switch rocker 78, thereby opening second switch 76.

FIG. 21 illustrates a situation in which switch activating pin 68 of thedriving arm 54 has now made contact with second switch rocker 78,thereby opening it and breaking the circuit which had energized themotor. Thus, the gate will then stop in the given position in which thedriving arm 54 with the attached slotted bracket 72 will have pulledgate 2 out of gate housing 8, thereby opening the aperture.

What is claimed is:
 1. A blast gate and controller for the applicationof vacuum pressure to particulate generating machines comprising: a. acontroller housing connectable to a gate housing, b. a controllermechanism contained within said controller housing, c. a gate slidablydisposed within said gate housing, d. said controller mechanismconnectable to said gate whereby said gate may be withdrawn and insertedwithin said gate housing. e. said gate housing having a first apertureand a corresponding second aperture, said first and second aperturescapable of being opened and closed by said gate, f. said first apertureconnectable to a duct leading to a vacuum and said second apertureconnectable to a duct leading to a particulate generating machine.